Automatic analyzer

The automatic analyzer includes a suction nozzle; a liquid transfer syringe; a suction channel which connects the suction nozzle and the liquid transfer syringe; a flow cell which is arranged in the middle of the suction channel; a detector for sample analysis which is arranged in the flow cell; a reaction auxiliary liquid vessel and a cleaning liquid vessel which store liquids to be sucked in by the suction nozzle; means for supplying a diluting fluid to the vessels; a cleaning tank for dumping liquid remaining in the vessels; and a controller for supplying the diluting fluid to the vessels when the remaining liquid is discharged from the vessels and thereafter having the diluted remaining liquid sucked into the flow cell via the suction nozzle and having the sucked remaining liquid discharged to the cleaning tank.